Protocol TGC09201 is a multi-center, double-blind, placebo-controlled, randomized study. A total of one hundred (100) adults with grade 3 chronic degenerative joint disease (DJD) of the knee joint (as determined by radiographic examination) will be enrolled into the study. TissueGene-C will be administered intra-articularly once via x-ray guidance. TissueGene-C will be administered at a dose of 3 x 10e7 cells. Patients receiving control treatment will receive a single normal saline injection.